We would like to use cinder blocks with recycled content, but have been warned that flyash rust will bleed through the stucco.

We are building a new home in Asheville, NC. The foundation will be block, or CMU. One provider includes recycled content. The competitor claims that the fly ash or cinders contain iron, which will rust and bleed through the stucco finish. Is that likely to be true?

We are building a new home in Asheville, NC. The foundation will be block, or CMU. One provider includes recycled content. The competitor claims that the fly ash or cinders contain iron, which will rust and bleed through the stucco finish. Is that likely to be true?

Your question was of interest to me as it highlights some of the misconceptions about fly ash. The short answer to your question is no, but the long answer brings...